Herbicide safener-binding protein of maize - Purification, cloning, and expression of an encoding cDNA
Herbicide safener-binding protein of maize - Purification, cloning, and expression of an encoding cDNA
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DOI：
10.1104/pp.116.3.1083
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发表时间：
1998-03-01
期刊：
影响因子：
7.4
通讯作者：
Walton, JD
中科院分区：
文献类型：
--
作者：
Scott-Craig, JS;Casida, JE;Walton, JD
二氯乙酰胺安全剂保护玉米(Zea Mays L.)对抗氯乙酰苯胺和硫代氨基甲酸酯除草剂的伤害。黄化玉米幼苗对安全剂[H-3](R，S)-3-dichloroacetyl-2，2，5-trimethyl-1，3-oxazolidine([H-3]SAF)有一个高亲和力的细胞质结合位点，这种安全剂结合活性被除草剂竞争性地抑制。经纯化后的SAFBP相对分子质量为39,000，经十二烷基硫酸钠-聚丙烯酰胺凝胶电泳法测定，等电点为5.5。针对纯化的SafBP制备的抗血清可特异性识别含有SafBA的黄化玉米和高粱(高粱)中的39-kD蛋白，但不能在缺乏SafBA的黄化小麦(Triticum aestivum L.)、燕麦(Avena sativa L.)、大麦(Hordeum vocgare L.)、烟草(Nictiana tabacum L.)或拟南芥中识别。SafBP在胚芽鞘中含量最丰富，在叶片中含量最少，与SafBA的分布一致。以纯化的蛋白水解肽为模板，用聚合酶链式反应方法克隆了SafBP的编码基因SBP1。表达SBP1的大肠杆菌细胞提取物具有很强的[H-3]SAF结合，与天然玉米蛋白的结合一样，被更安全的二氯氰胺和除草剂S-二丙基硫代氨基甲酸乙酯、甲草胺和异丙甲草胺竞争抑制。SBP1编码一个酚类O-甲基转移酶，但SafBP不编码邻苯二酚或咖啡酸的O-甲基化。其编码基因的获得为评价SafBP在相关安全剂和除草剂中的作用开辟了实验途径。
Dichloroacetamide safeners protect maize (Zea mays L.) against injury from chloroacetanilide and thiocarbamate herbicides. Etiolated maize seedlings have a high-affinity cytosolic-binding site for the safener [H-3](R,S)-3-dichloroacetyl-2,2,5-trimethyl-1,3-oxazolidine ([H-3]Saf), and this safener-binding activity (SafBA) is competitively inhibited by the herbicides. The safener-binding protein (SafBP), purified to homogeneity, has a relative molecular weight of 39,000, as shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and an isoelectric point of 5.5. Antiserum raised against purified SafBP specifically recognizes a 39-kD protein in etiolated maize and sorghum (Sorghum bicolor L.), which have SafBA, but not in etiolated wheat (Triticum aestivum L.), oat (Avena sativa L.), barley (Hordeum vulgare L.), tobacco (Nicotiana tabacum L.), or Arabidopsis, which lack SafBA. SafBP is most abundant in the coleoptile and scarcest in the leaves, consistent with the distribution of SafBA. SBP1, a cDNA encoding SafBP, was cloned using polymerase chain reaction primers based on purified proteolytic peptides. Extracts of Escherichia coli cells expressing SBP1 have strong [H-3]Saf binding, which, like binding to the native maize protein, is competitively inhibited by the safener dichlormid and the herbicides S-ethyl dipropylthiocarbamate, alachlor, and metolachlor. SBP1 is predicted to encode a phenolic O-methyltransferase, but SafBP does not O-methylate catechol or caffeic acid. The acquisition of its encoding gene opens experimental approaches for the evaluation of the role of SafBP in response to the relevant safeners and herbicides.